Spotify (finally) launches in the U.S.

After a long crescendo of promises and speculation, Spotify has launched in the United States at last.

The music-streaming service allows users to stream what it says are "millions" of songs both from their computers and from mobile devices. Spotify relies heavily upon playlists, which users can create as soon as they boot up the service. Users can search through the company's tracks and simply drag and drop songs to a given list. The service also allows people to import MP3s to bolster the music player's offering. Once the playlists are created, they can be accessed from anywhere a user loads Spotify.

Spotify offers a free, ad-supported service for those who want to listen to tracks on their computers. Users can also sign up for the company's $4.99 per month unlimited plan, which allows them to stream "millions of tracks" with no time limits and no ads. The company's $9.99 per month premium plan includes all the same features, but adds the ability to listen without a Web connection and on mobile devices. Premium also boasts enhanced sound quality.

The streaming service also includes a social element, letting folks share their music with others. In order to do so, users can drag and drop music to friends or share on Facebook, Twitter, SMS, and e-mail. According to the company, 250 million playlists have been shared around the world so far.

Spotify debuted in Europe in 2008, and has attracted a loyal following by making it easy for users to stream tracks they know and find new songs. At last count, Spotify, which offers its customers free, ad-supported tracks, as well as paid subscriptions, said that it had 13 million music tracks available to its European customers. The company said today that there are 15 million songs available to U.S. subscribers.

U.S.-based consumers hoping to get in on the fun became more excited about the anticipated launch as Spotify started to sign music labels in the States. Spotify inked a deal with Sony in January, and then reportedly formed partnerships with the other major labels earlier this year.

As Spotify looks ahead, the company is also touting some of the things it has already achieved. It announced today that it now has 10 million registered users in Europe, and over 1.6 million paying subscribers.